The present invention relates to a method and device using a flame for producing synthetic gas.
The combustion of hydrocarbons, such as natural gas, in an atmosphere deficient in oxygen, leads to the formation of carbon monoxide (CO), hydrogen (H.sub.2) but also carbon dioxide (CO.sub.2) and water (H.sub.2 O).
For example, if a mole of methane (CH.sub.4) is combusted with 0.7 mole of oxygen, 54.9% mole of hydrogen (H.sub.2) is obtained; 31.6% mole of carbon monoxide (CO); 1.7% mole of carbon dioxide (CO.sub.2) and 11.7% mole of water (H.sub.2 O) in adiabatic equilibrium.
However, by the very combustion process, intermediate hydrocarbons are present, with formation of less CO and H.sub.2, but more CO.sub.2 and H.sub.2 O. Tests have been carried out for minimizing this phenomenon. The conversion into CO and H.sub.2 is all the better if the walls of the reactor are adiabatic (the shape of the reactor must not allow radiation losses).
There is no major problem for O/C ratios close to 1.5 mole/mole, but for lower ratios it is necessary to preheat the gases. In the presence of hydrocarbons heavier than methane, the formation of soot may limit the lowering of the O/C ratio.